I. Field of the Invention
The present invention relates to alarm systems. More particularly, the present invention relates to an alarm system having sensors positionable along the top or sides of a door opening so as to announce when an article strikes one or more of the sensors, thus alerting a vehicle operator that the size of the article is too great to pass through the door.
II. Background of the Invention
The movement of wheeled vehicles around, between and through structures often creates considerable risk of damage. For example, because of the narrowness of throughways and the restricted height of parking structures or parking decks, automobiles navigating such structures frequently risk impacting pillars, walls, or ceilings. Similarly, automobiles driving around and through drive-up windows at fast-food restaurants or in banks suffer the same potential hazards. Articles of manufacture are frequently moved within the manufacturing facility, a warehouse, or a retail store before finding their way to the end user. Frequently these objects are moved through doors or other passageways formed in or adjacent to the building. Frequently these articles are moved by hand, but even more frequently such articles are moved by motorized vehicles such as high-lows.
The construction of a typical high-low is such that the operator is positioned in such a place so as to have an unobstructed view of his environment at such time as there is no load on the vehicle. However, when the vehicle is loaded with one or more boxes, crates, or uncrated but bulky goods, the operator's view is often obstructed, particularly when the grids are elevated to enable the vehicle to move about. In such circumstances, the first point of view to be compromised is the view directly in front of the operator.
The result of this obstructed view is too frequently damaged goods and a damaged header above the door frame. Not only is the damage to the header costly, frequently ranging in the thousands of dollars, this damage also compromised the structural integrity of the door as a whole, even when correctly repaired. This presents a safety problem. A similar situation arises when a load is overly wide for a door opening. When the operator attempts to pass through the doorway with such a load, again the goods are damaged as well as the sides of the door frame.
Little, if anything, has been done to alleviate this problem. A variety of alarm systems are known of both the mechanical and electronic type. These include, for example, U.S. Pat. No. 3,612,460, issued Oct. 12, 1971, to Smith, U.S. Pat. No. 5,089,806, issued Feb. 18, 1992, to Willis et al., U.S. Pat. No. 5,230,296, issued Jul. 27, 1993, to Giltz et al., and U.S. Pat. No. 5,474,016, issued Dec. 12, 1995, to Haney. However, these alarm systems, without more, fail to effectively or efficiently address the problems associated with the movement of goods and boxes within the shop, warehouse, or place of manufacture. Accordingly, there remains wanting a system which will protect the door frame of a door during movement of articles therethrough.